6bcy

From Proteopedia

Complex of 14-3-3 theta with an IRSp53 peptide phosphorylated at T360

Structural highlights

6bcy is a 8 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.3Å
Ligands:	, , , , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

BAIP2_HUMAN Adapter protein that links membrane-bound small G-proteins to cytoplasmic effector proteins. Necessary for CDC42-mediated reorganization of the actin cytoskeleton and for RAC1-mediated membrane ruffling. Involved in the regulation of the actin cytoskeleton by WASF family members and the Arp2/3 complex. Plays a role in neurite growth. Acts syngeristically with ENAH to promote filipodia formation. Plays a role in the reorganization of the actin cytoskeleton in response to bacterial infection.^[1] ^[2] ^[3] ^[4]

Publication Abstract from PubMed

Filopodia are precursors of dendritic spines and polarized cell migration. The I-BAR-domain protein IRSp53 is a key regulator of filopodia dynamics that couples Rho-GTPase signaling to cytoskeleton and membrane remodeling, playing essential roles in neuronal development and cell motility. Here, we describe the structural-functional basis for 14-3-3-dependent inhibition of IRSp53. Phosphoproteomics, quantitative binding and crystallographic studies demonstrate that 14-3-3 binds to two pairs of phosphorylation sites in IRSp53. Using bicistronic expression, we obtain an IRSp53 heterodimer in which only one subunit is phosphorylated, and show that each subunit of IRSp53 independently binds one 14-3-3 dimer. A FRET-sensor assay using natively phosphorylated IRSp53 reveals opposite conformational changes upon binding of activatory (Cdc42, Eps8) or inhibitory (14-3-3) inputs. Finally, we show that 14-3-3 inhibits IRSp53 binding to membranes. Collectively, our findings support a mechanism whereby phosphorylation-dependent inhibition of IRSp53 by 14-3-3 counters membrane binding and interactions with Cdc42 and downstream cytoskeletal effectors.

Mechanism of IRSp53 inhibition by 14-3-3.,Kast DJ, Dominguez R Nat Commun. 2019 Jan 29;10(1):483. doi: 10.1038/s41467-019-08317-8. PMID:30696821^[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Miki H, Yamaguchi H, Suetsugu S, Takenawa T. IRSp53 is an essential intermediate between Rac and WAVE in the regulation of membrane ruffling. Nature. 2000 Dec 7;408(6813):732-5. PMID:11130076 doi:http://dx.doi.org/10.1038/35047107
↑ Krugmann S, Jordens I, Gevaert K, Driessens M, Vandekerckhove J, Hall A. Cdc42 induces filopodia by promoting the formation of an IRSp53:Mena complex. Curr Biol. 2001 Oct 30;11(21):1645-55. PMID:11696321
↑ Yamagishi A, Masuda M, Ohki T, Onishi H, Mochizuki N. A novel actin bundling/filopodium-forming domain conserved in insulin receptor tyrosine kinase substrate p53 and missing in metastasis protein. J Biol Chem. 2004 Apr 9;279(15):14929-36. Epub 2004 Jan 29. PMID:14752106 doi:http://dx.doi.org/10.1074/jbc.M309408200
↑ Vingadassalom D, Kazlauskas A, Skehan B, Cheng HC, Magoun L, Robbins D, Rosen MK, Saksela K, Leong JM. Insulin receptor tyrosine kinase substrate links the E. coli O157:H7 actin assembly effectors Tir and EspF(U) during pedestal formation. Proc Natl Acad Sci U S A. 2009 Apr 21;106(16):6754-9. doi:, 10.1073/pnas.0809131106. Epub 2009 Apr 6. PMID:19366662 doi:10.1073/pnas.0809131106
↑ Kast DJ, Dominguez R. Mechanism of IRSp53 inhibition by 14-3-3. Nat Commun. 2019 Jan 29;10(1):483. doi: 10.1038/s41467-019-08317-8. PMID:30696821 doi:http://dx.doi.org/10.1038/s41467-019-08317-8